For decades, scientists believed that Turkey’s Tuz Gölü Fault moved sideways at a rate of 4.7 millimeters per year. Satellites orbiting Earth tracked this sideways sliding motion, and geologists built their earthquake models around it. But rocks told a completely different story. Ancient lava flows in central Anatolia showed that the ground actually moved vertically, not sideways.
This discovery flipped everything scientists believed about one of Turkey’s most dangerous faults. Researchers at Curtin University, led by Professor Axel Schmitt, studied lava flows from the Hasandağ volcano that were between 151,000 and 38,800 years old.
The flows had been disrupted by the fault, and by measuring how far the rocks had moved, the team discovered the truth: the fault had pulled Earth’s crust apart vertically, moving at a rate of 0.90 to 1.23 millimeters per year. Strike-slip motion essentially stopped. The research, published in Nature in 2025, demonstrated that GPS satellites were unable to detect this slow vertical movement.
Satellites excel at tracking sideways motion but struggle with gradual up-and-down movement. Over 100,000 years, this vertical motion created a separation of 123 meters—far too slow for modern satellite systems, which can only measure recent decades.
The team employed a specialized dating technique called zircon double-dating, which involves analyzing uranium-thorium and helium isotopes in mineral crystals to track rock displacement with exceptional precision.
Why This Discovery Changes Earthquake Safety
This finding is of enormous significance for the 80 million people residing in central Anatolia, particularly those living near major cities such as Ankara, Konya, Aksaray, and Kayseri. The Tuz Gölü Fault stretches 200 kilometers near Lake Tuz, 105 kilometers northeast of Konya, and sits where three continental plates collide: the Eurasian, Arabian, and African plates.
This collision creates what geologists call a tectonic crossroads—a place where Earth’s crust stretches and breaks under enormous pressure. Geologists had classified this fault as a strike-slip fault—one where blocks slide sideways like two hands rubbing together.
Scientists incorporated this classification into building codes and earthquake safety maps across the region. But normal faults, where blocks pull apart vertically, create completely different earthquake patterns. They send strong vertical ground motion upward, not sideways motion. Buildings designed for strike-slip earthquakes may collapse under normal-fault earthquakes.
The Helvadere segment of this fault poses the highest risk, with scientists predicting earthquakes between magnitude 6.8 and 7.0. Evidence suggests the last major rupture occurred roughly 5,500 years ago, meaning the fault has accumulated enormous stress since then.
Turkish authorities, including the Disaster and Emergency Management Authority, now must completely reevaluate earthquake risk maps and update building codes across the entire region to account for vertical ground shaking.
Lessons for Understanding Earth’s Dangers
This discovery raises fundamental questions about how scientists monitor faults worldwide. A 200-kilometer fault in an active seismic zone somehow stayed misclassified for decades despite dense GPS coverage. How many other faults around the world might have hidden behavior?
The zircon dating technique that revealed this secret now opens new possibilities for research. Scientists measure minerals, such as zircon crystals, in rocks using uranium-thorium and helium isotope analysis. When faults displace these crystals, their position changes, but their age stays the same, revealing exactly how far rocks have moved over thousands of years.
This method reveals geological secrets that modern instruments cannot capture. International research teams are now applying this technique to other faults that have been historically classified as strike-slip, in search of hidden vertical motion throughout the Anatolian region.
The methodology also helps scientists improve earthquake forecasting, volcanic hazard assessment, and even subsurface mapping for carbon capture projects. Ultimately, this research teaches an essential lesson: rocks preserve histories that satellites cannot read. Geological timescales extend far beyond human lifespans and instrumental records.
Understanding Earth’s dangers requires combining modern technology with ancient stone records spanning hundreds of thousands of years.
Sources
Daily Galaxy, November 29, 2025
Curtin University press release, April 30, 2025
Nature Communications Earth & Environment, November 2025
Structural geology literature
Geology journal articles, 2020-2025
Wikipedia, Extensional Fault article